Examples of applications of wireless communications include cordless telephones, paging, wireless local loops, personal digital assistants (PDAs), Internet telephony, and satellite communication systems. A particularly important application is cellular telephone systems for mobile subscribers. As used herein, the term “cellular” system encompasses both cellular and personal communications services (PCS) frequencies, or any other frequencies upon which networks for wireless voice and/or video telephony may operate. Various over-the-air interfaces have been developed for cellular telephone systems including, e.g., frequency division multiple access (FDMA), time division multiple access (TDMA), and code division multiple access (CDMA). In connection therewith, various domestic and international standards have been established including, e.g., Advanced Mobile Phone Service (AMPS), Global System for Mobile (GSM), and Interim Standard 95 (IS-95). IS-95 and its derivatives, IS-95A, IS-95B, ANSI J-STD-008 (referred to collectively below as IS-95), and proposed high-data-rate systems are promulgated by the Telecommunications Industry Association (TIA, Arlington, Va.) and other well-known standards bodies.
Cellular telephone systems configured to comply with a version of an IS-95 standard employ CDMA signal processing techniques to provide highly efficient and robust cellular telephone service. Exemplary cellular telephone systems configured substantially in accordance with the use of one or more of the IS-95 standards are described in U.S. Pat. Nos. 5,103,459 and 4,901,307.
The IS-95 standards subsequently evolved into third-generation or “3G” systems for wireless cellular telephony, such as cdma2000 and WCDMA, which provide more capacity as well as high-speed packet data services. Variations of cdma2000 include cdma2000 1xRTT (radio transmission technology, also called “1x”), as described in the documents IS-2000 (TIA) and C.S0001 to C.S0006 (Third Generation Partnership Project 2 (3GPP2), Arlington, Va.), cdma2000 1xEV-DO (1x Evolution—Data Optimized, also called “DO” or High Rate Packet Data (“HRPD”)), as described in the document IS-856 (TIA), DO-Revision A as standardized in C.S20024-A (also known as IS-856A), entitled “cdma2000 High Rate Packet Data Air Interface Specification,” v. 1.0, March 2004 or v. 2.0, July 2005 (3GPP2), and cdma2000 1xEV-DV (1x Evolution, Data/Voice). A 1x system offers a peak data rate of 153 kbps, while an HRPD system offers a set of data rates ranging from 38.4 kbps to 2.4 Mbps, at which an access point (AP) may send data to a subscriber station (also referred to as a mobile station (MS) or access terminal (AT)). Because the AP is analogous to a base station in a system for cellular telephony, the terminology with respect to cells and sectors in such a system for wireless packet data services is the same as with respect to voice systems.
Given the growing demand for wireless data applications, the need for very efficient wireless data communication systems has become increasingly significant. One such wireless data application is the transmission of data packets that originate or terminate at packet-switching networks. Various standardized techniques exist for transmitting packetized traffic over packet-switching networks so that information arrives at its intended destination. One class of such techniques is described in the Wireless IP Network Standard IS-835 (e.g., document IS-835D), which specifies operations of Packet Data Serving Nodes (PDSN). A PDSN is responsible for establishing, maintaining, and terminating a packet data session with an access terminal, such as a Point-to-Point Protocol (PPP) session over the Internet.
A subscriber station may be configured to execute various applications that receive data from and/or transmit data to the network. These applications may have very different tolerances and requirements in terms of how this data is transported (also called “quality of service” or “QoS” requirements). Non-real-time applications such as e-mail and file transfer (e.g., mp3 files) have variable bandwidth requirements but lax delay and loss requirements. Retransmission of missing or corrupted frames may be useful in non-real-time applications. Telephony applications may have low bandwidth requirements but have low tolerance for frame delay and for variability in the delay (also called “jitter”). Typically the latency from one handset to the other should not exceed 250 msec, and jitter should not exceed 20 msec. While the RLP (Radio Link Protocol) commonly used on a cdma2000 air interface allows for retransmission of frames, such retransmission is not useful for real-time traffic.
A subscriber station may also be configured to execute one or more multimedia applications having different QoS requirements. Streaming of audio and/or video content can tolerate some degree of startup delay and can be buffered to increase tolerance to jitter, while bandwidth and loss tolerance characteristics may vary depending on the particular codec. Interactive applications such as online gaming typically have low bandwidth requirements but very strict delay requirements. Video conferencing has high bandwidth requirements and also requires low delay and jitter.
It may be desirable to support QoS on a per-application-flow basis. A particular QoS treatment for a flow may be negotiated between two points of a packet data transmission (e.g., between a subscriber station and a base station, or between a subscriber station and a PDSN). A request for a particular QoS treatment may specify the bandwidth of the traffic channel, the scheduling of packet data, the scheduling of transmission packets over-the-air, delay sensitivity of the contents, or other factors that may be deemed relevant by a network carrier or service provider. Obtaining a desired level of service may involve requesting QoS processing operations from more than one network entity (e.g., from a base station and from a PDSN).